select * from (select *, ROW_NUMBER() OVER(partition by [FLID],[ZBM],[MC] Order by [FLID],[ZBM],[MC] ) AS RowNumber
from [MaterialClassFLMX])a where a.RowNumber>1
delete a from (select *, ROW_NUMBER() OVER(partition by [FLID],[ZBM],[MC] Order by [FLID],[ZBM],[MC] ) AS RowNumber
from [MaterialClassFLMX])a where a.RowNumber>1